Projection apparatus for the creation of illusory effects



Dec. 10, 1946. R. B. JOHNSON 2,412,340

PROJECTION APPARATUS FOR THE CREATION 0E ILLUsoRY EFFECTS Filed Sept. 8, 1944 2 Sheets-Sheet 1 Dec. 10, 1946. R. B. JOHNSON PROJECTION APPARATUS FOR THE CREATION OF ILLUSORY EFFECTS Filed Sept. 8, 1944 2 SheetS-Sheet 2 52 @4 fafa 62 f4 5 A n F INVENTOR HegwdBQ/biamoiz ATTORNEY Patented Dec. 10, i946 u a s PROJECTION APPARATUS FOR THE CREATION OF ILLUSOBY EFFECTS Reynold B. Johnson, Binghamton, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application September 8, 1944, Serial No. 553,188

4 Claims. l

'I'he projection apparatus comprising the present invention is primarily adapted for use in the creation of illusory effects upon a projection screen simulating muzzle ilash as it exists in the tiring of a dual gun weapon of the type commonly employed in a turret installation of a combat plane, The invention is designed for use in connection with training apparatus of the type shown in my co-pending application Serial No. 553,167, filed September 8, 1944, for Artillery training apparatus and method.

In. the apparatus shown and described in the above mentioned co-pending application, a dummy weapon is employed for aiming at a moving target projected upon a, motion picture projection screen. This weapon is in the form `of a turret installation closely simulating an actual turret installation and having a pair of spaced dummy weapons carried on a tiltable gun mount. The gunner undergoing training is seated in a compartment between the two weapons and he is provided with most of the usual turret accoutrements' common to such installations, including dual trigger devices and a gun sight. The training apparatus further vincludes a trace trainer projector which is located behind the dummy weapon installation for the purpose of placement projection of tracer effects on the screen which are correlated with the aiming and firing oi.' the dummy weapons.

The present invention is designed to further enhance the optical effects produced upon the student gunner by creating the illusion of muzzle flash on the screen and in accomplishing this purpose a flash of light may be seen by the gunner when looking through the gun sight as each tracer shot is fired. The flash appears to leave the gun muzzle and converge upon the screen at the point of aim just as the tracer shot appears.

The projection unit comprising the present invention is mounted upon the turret gun cradle or gun mount at one side Vof the gun sight and is bodily movable with the cradle. The device is synchronized electrically with the turret controls so as to become operative only when tracer shots are discharged at the screen.

The provision of an apparatus o'f the character set forth being the principal object of the invention, a further object thereof 'is to provide a projection unit of this type which is relatively simple in its construction and which is comprised of a minimum number of moving parts and which, consequently, is unlikely to get out of order. l

Another object ofthe invention is to provide such an apparatus which is electrically con-l 2 trolled, thereby facilitating synchronization of the flash with the electrical tiring of the dummy weapon. o

A still further object of the invention is to provide a small portable projection apparatus capable oi being attached to or removed from the dummy weapon at will and capable of being connected to the dummy weapon installation by detachable plug-ln connections. v

In carrying out the above mentioned object, the invention contemplates the provision of a continuously illuminated light source adapted to cast its light upon a movable rror which is capable of oscillation about an axis. Light issuing from the source and striking the mirror is deflected from the surface of the moving mirror onto a reector and from thence. onto the screen,l the tendency being to project a moving beam of light onto the screen and cause the same to move across the screen from left to right and from right to left alternately. Because of the fact that such a beam of light in passing across the screen in that region thereof which exists directly at the point of aim would ordinarily tend to obscure the tracer effects produced by the training projector, means are provided yfor blanking out the spot as it approachesl the point of aim. Toward this end, shutter means are provided for the light source which become operable periodically to block light issuing from the source at a predetermined time. The provision o! an apparatus possessing this feature is a still further important object of the present invention.

Further objects and advantages of the invention not at this time enumerated will become more readily apparent as the nature of the invention is better understood. y

In the accompanying two sheets of drawings forming part of this specication, one embodiment of the invention is shown. In these drawmgs:

Fig. 1 is a side elevational view of the projection unit with one side wall of its casing improved and certain other parts being broken away to more clearly reveal the nature of the invention.

Fig. 2 ls a sectional view taken substantially along the line 2-2 of Fig. 1.

Fig, 3 is a sectional view taken substantially along the line 3-3 of Fig. l.

Fig. 4 is a. sectional view taken substantially along the line 4-4 of Fig. 1.

Fig. 5 1s a diagrammatic vlewrshowing the electrliconuections'for the projection apparatus.

. 3 I. Referring now to the drawings in detail, the

apparatus involves in its general organization a rectilinear box-like casing 8 adapted to be detachably secured in a suitable position tothe tiltable gun mount or cradle of a dummy weapon 1 substantially as-shown in my co-pending application above referred to. The casing 8 includes a base plate I8 on which there is mounted a bracket I2 which serves to support a mounting I4 for a lamp l.- A lens I6 mounted in a bracket I8 serves to concentrate light issuing from the lamp l into a beam and to project-the latter 'against the surface of a movable mirror 20 positioned behind the lamp. From'the movable mirror'28'the light t beam is projected againstthe surface of a stationary mirror 22 mounted on a, bracket -24 supl ported on the side pieces'- 26 of an inverted l U-shaped frame 28 supported on the base plate I0. From the stationary mirror 22 the light beam is projected onto a screen (not shown) associated with the trace trainer apparatus.

The movable mirror 20 is mounted on a fixture 38 which in turn is mounted on a horizontal rock shaft 32 suspended in brackets 34 and 36. The

movable mirror 20 is inclined with respect to the e shaft 32 in such a manner that 'light issuing 1 from the lens I6 will be reflected generally upwardly against the stationary mirror 22 which is of elongated design andextends completely across I theunit between the side members 26.

'A pair of solenoids 38 and 40 are mounted on a support 42 carried by the base plate I8 and are i '4 A 16 in such a manner that upon oscillation of thel shaft 54 these lateral portions of the operating arms 66 are adapted to alternately engage the shutter ann 16 to bring the shutter 18 directly m of its stroke in either direction. This permits' a -ash of light upon the screen to sweep in one direction or the other `inwardly of the screen untn .the shutter iaheoomes eseotive to b1ook A light rays issuing from the lamp l. After this Y occurs no further light is permitted to reach the screen until after the mirror has completed its stroke. 'I'he movements of the shutter 18 and of the mirror 20 are so correlated that the net result consists of a flash of lightwhich appears on the screen ea'ch time 'a tracer shot is fired.

. This flash alternately sweeps inwardly from the sides of thel screen and converges toward the point of aim of the dummy guns associated with provided with cores 44 that are pivoted medially of respective links 46, whichinturn are pivoted to xed lugs 48 mounted onthe upper ends of the solenoids. The free end of each link 46 is pivotally attached lto a connecting rod or link 50 and the lower ends-of the links 58 are secured to theopposite ends of a cross head 52 centered on the shaft32. The solenoids 38 and 46 exist in respective electrical circuits by means of which l alternate energization thereof is made possible to cause oscillation of the cross head 52 and conse- 3 quent oscillation of the shaft 32 and movable l mirror 28 about a horizontal axis. The electrical circuits for the solenoids 38 `and 40 will be pointed l out subsequentlyduring the descriptionof the j electrical diagram for the unit. l The bracket 36 is. comparatively wideand in addition to performing a supportfor the rock shaft 32 also serves to rotatably support one end of a second rock shaft 54, the other end of which shaft is rotatably supported in a bracket 56 positioned near and to one side of the lamp assembly. An arm 58 secured to the` rock shaftv32 w projects outwardly therefrom and is provided with a slot 60 adjacent its free end. A similark arm 62 carried by the shaft 54 is provided with a pin 64 adjacent its outer lend which passes through the slot 68- for the purpose of mechani- 1 cally coupling thetwo shafts 32 and 54 together. It will be seen that by the arrangement of parts just described the oscillatory motion of the shaft 32 will be transmitted to the shaft 54. The t forward end of the shaft 54 immediately behind lthe bracket 36 has mounted thereon a pair of `shutter operating arms '66 which project out- `wardly from the shaft 54 and the ends. of which `are turned laterally as at 68. .-Abracket 10 see cured to the base plate I0 serves to support adjacent its upper end a rockrv shaft 12 Vfrom which there projects laterally a shutter member 14 including a shutter arm 16 and a shutter proper f 18. The two laterally extending` portions 68 of the operating arms 66 straddle the shutter arm the trace trainer installation. These flashes of light are observed by the operator seated in the turret compartment of the assembly on opposite sides of the twol gun units. v

A cover plate or casing including side walls 82, a top wall 84 and a rear wall 86 is provided for the mechanism just described. The front end of the casing 8 is open in theupper regions thereof and a shield as 'is associated with the 'Y casing 8 to restrict issuance of light from the lamp n l and confine the light to the mirror 28. VThe passage of light from the lamp l and its deection by the mirrors 26 and 22 onto the screen is graphically illustrated by means of small arrowsxain Fig. 1.

Referring now to Fig. 5 -wherein the circuit diagram for the projection apparatus is disclosed, the lamp Z'receives energization from the secondary coil s of a transformer T having a primary winding p adapted to be energized from a source of current S which may, if desired, be the usual 11G-volt. 60cycle alternating household current. .y

'Ihe solenoid 38 is provided with a winding Si and the solenoid 40 is provided vwith a, winding S2, the two windings -being connected together in parallel and having a common lead a in which there is interposed a source of current whichmay, if desired, be a battery B. `'I'he windings SI and Si` are connected by wires b and c to respective brushes b' and b" associated with a rotor r adapted to be continuously driven from a motor M. 'I'he rotor r carries a movable contact C operablev upon rotation of the rotor r to alternately engage the brushes b' and b" and thus alternately energize the solenoids 38 and 40. A

switch tc which may be in the form of a trigger mechanism serves to open the circuit of the motor and the common lead a of the solenoid windings SI and S2.

The invention is not to be nmited to the exact arrangement of parts shownin the accompany-v Only insofar as the invention has been particularly pointed out in the accompanying claims is the same to be limited.

What is claimed is: y l. In a projection apparatus for producing moving light effects which are representative of tracer bullet flash upon a projection screen, a

' movable mirror mounted for oscillation about an axis, a light source positioned in front of said mirror, a movable shutter positioned between said light source and mirror andmovable from a position out of the path of light issuing from said source and passing to the screen to a position in the path of movement of such light, means operatively connecting said mirror and shutter to synchronize the movements thereof whereby said shutter assumes an inoperative position when clined with respect to the axis of said shaft, an

electromagnet operable upon energization thereof to move said rock shaft in one direction to an extreme position, a second electromagnet operable upon energization thereof to move said rock shaft in the opposite direction to an extreme position, a second rock shaft mounted for -rotation about a horizontal axis, a light source positioned in front of said mirror, a shutter secured to said second rock shaft and movable with the shaft from an inoperative 4position wherein it is out of the path of movement of .light issuing from said source and proceeding to the mirror to an operative position wherein it intercepts such light, means for alternately energizing said electromagnets to impart oscillating movement to said first mentioned rock shaft, and means including a lost motion connection operatively connecting said rock shafts to transmit motion from the former to the latter.

3. In aV projection apparatus for producing moving light eects upon a projection screen, a horizontal rock shaft, a mirror mounted upon said rock shaft for oscillation therewith and inclined with respect to the axis of said shaft, an electromagnet operable upon energization thereof to move said rock shaft in one direction to an -extreme position, a second electromagnet operable upon energization thereof to move said rock sition, a second rock shaft mounted for rotation about a horizontal axis, alight source positioned in front of said mirror, a shutter secured to said second rock shaft and movable with the shaft from an inoperative position wherein it is out of the path of movement of light issuing from said source and proceeding to the mirror to an operative position wherein itintercepts such light, means for alternately energizing said electromagnets to impart oscillating movement to said first mentioned rock shaft, a third rock shaft mounted for oscillation about a horizontal axis, means operatively connecting said first mentioned rock shaft to said third mentioned rock shaft to transmit motion from the former to the latter, and means including a lost motion connection operatively connecting said third mentioned rock shaft l to said second mentioned rock shaft to transmit motion from the former to the latter.

4. In a projection apparatus for producing moving light effects upon a projection screen, a rock shaft mounted for rotation about a horizontal axis, a mirror mounted on said rock shaft for oscillation therewith and inclined with respect to the axis thereof, an electromagnet operable upon energization thereof to move said rock shaft in one direction to an extreme position, a second electromagnet operable upon energization thereof to move said rock shaft in the other direction to an extreme position, a second rock shaft mounted for rotation about a horizontal axis, a

. light source positioned in front .of said mirror, a

shutter carried by said second rock shaft and movable from an inoperative p0siti0n where it is out of the path of light issuing from said source and proceeding so the movable mirror to an operative position where it intercepts such light, a third rock shaft mounted for oscillation about a horizontal axis, an arm secured to said first mentioned rock shaft and projecting laterally therefrom, an arm secured to said third mentioned rock shaft and projecting laterally therefrom, there being a slot in one of said arms, a pin carried by the other arm and projecting through said slot whereby motion of said first mentioned rock shaft is imparted to said third mentioned rock shaft, a pair of divergingarms secured to said third mentioned rock shaft and having 'laterally turned ends which straddle said shutter, the distance between'said laterally turned ends being greater than the width of said shutter in the region of contact therewith, -and means shaft in the opposite direction to 'an extreme poi'or alternately energizing said electromagnets.

REYNOLD B. JOHNSON. 

